International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 10, Issue 1, pp: (21-27), Month: April 2022 - September 2022, Available at: www.researchpublish.com
Effect of Shaft Height on Base Shear of Elevated Intze Water Tanks Nyabuto Onderi Andrew1, Siphila Wanjiku Mumenya2 1
M.Sc. Structural Engineering student
2
Doctor, Consulting Engineer and a Senior lecturer in Civil Engineering 1,2
University of Nairobi, Nairobi, Kenya Published date: 16-April-2022
Abstract: Overhead storage reservoirs such as elevated Intze tanks store water, petroleum products, and other liquids for effective distribution. In this study, four (10, 12,14, and 16) different heights of an elevated shaft in meters of Intze tank are assumed to carry a similar capacity of water. The diameter of the tank and height change simultaneously maintaining the same capacity in rising scenarios. The dynamic wind pressure analysis was carried out as per the American Institute stand ASCE-7, 2010 in which the impulse and convective pressure vary and are assumed hydrostatically on tank walls. The tank RCC analysis was also done in STAAD.Pro. V8i as per Indian standard IS:456 for reinforced concrete works. Variation in the base shear forces was observed for both tanks to increase from 289.94 kN to 362.98 kN for 10 m to 16 m shaft height. Keywords: Intze Water Tank, Equivalent Static Load, DL-Dead load, LL- Live Load and WL – Wind Load.
I. INTRODUCTION Liquids obtained from stockpiled storage facilities save on fundamental logistics on sufficient supply for various uses of the intended liquid. Water as other chemicals is preferably stored in elevated water tanks for domestic use, agricultural supply, industrial use, and hazard mitigation measure such as firefighting [1]. Reinforced concrete overhead water tanks, steel staged overhead tanks and elevated staged plastic tanks have been used both in domestic, industrial, and municipal facilities for decades. The design of the stockpiled storage facility is guided by capacity, population, region terrain, seismic effects, and efficiency intended for the distribution as the main purpose. Distribution being the key purpose for elevating storage tanks, does not necessarily serve the capacity purpose as compared to surface and subsurface tanks. Civil engineers over decades have worked towards beating constraints of capacity by varying staging shape and tank shape to achieve distribution aims such as sufficient and continuous flow, wider distribution, and many others. The geographical location of Kenya does not put it vulnerable to intense natural disasters like earthquakes, cyclones, and hurricanes. Although the country is enjoying its geographical benefits, the future is unknown by reference to the existing fault lines along the Great Rift valley which expose the country to intense seismic disturbance. Among the natural calamities, wind serves as the leading cause and distributor of various storms such as cyclones that occur along coastal shores and Kenya borders the Indian Ocean. The general understanding drives civil engineers to design and analyze tall structures against overturning and seismic disturbances. Elevated water tanks respond to natural forces and loadings like the tall structures despite the height since they consist of slender support systems and a lump of mass at the top. The loading nature makes the tank critical and more vulnerable to shear failure and overturning from lateral and axial forces as it assumes a single degree of freedom.
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